There are fundamentally two different types of vehicle navigational systems. The first system makes use of stored map displays wherein the maps of a predetermined area are stored in the invehicle computer and displayed to the vehicle operator or driver. The maps, knowing the location where the vehicle started and where it is to go, will highlight the direction and the driver will have to read the display and follow the route. One such stored map display system offered by General Motors on their 1994 Oldsmobile, uses Global Positioning System (GPS) satellites and advanced dead reckoning techniques to determine a precise location. The driver enters details of the desired destination into an on-board or invehicle, computer, in the form of specific address, a road intersection, etc. The stored map is displayed and the operator then pinpoints the desired destination. The on-board computer then calculates the most efficient route. The on-board computer then displays on a display unit, the distance to and the direction of each turning maneuver in easy-to-read graphics and also includes a voice prompt.
The second system, such as the Siemens Ali-Scout.TM. system, requires that the driver key-in the destination address, in geodetic coordinates, into the invehicle computer. A compass means located in the vehicle then gives a "compass" direction to the destination address. Such a "compass" direction is shown in easy-to-read graphics as an arrow on a display unit indicating the direction the driver should go. Along the side of the road are several infrared beacon sites which transmit data information to the properly equipped vehicle relative to the preferred routing to the next adjacent beacon sites. From all of the data the invehicle computer receives, the invehicle computer selects the desired beacon data information to the next beacon along the route direction to the final destination and displays a graphic symbol for the vehicle operator to follow and the distance to the desired destination. There is no map to read, only a simple graphic symbol and a voice prompt telling the vehicle operator where to turn and when to continue in the same direction.
U.S. Pat. No. 4,350,970, assigned to Siemens AG and issued on Sep. 21, 1982 to von Tomkewitsch and entitled "Method for Traffic Determination in a Routing and Information System for Individual Motor Vehicle Traffic" describes a method for traffic management in a routing and information system for motor vehicle traffic. The system has a network of stationary routing stations, each located in the vicinity of the roadway, which transmit route information and local information concerning its position to passing vehicles. The route information which is transmitted is the preferred routing to all beacons and zones adjacent to the beacon site. The vehicle navigation system then selects a route from all the routes transmitted by the beacon.
The trip destination address, via geodetic coordinates, is loaded by the vehicle operator into an onboard device, a navigation processor, in the vehicle and by dead reckoning techniques a distance and direction graphic is displayed. The first routing station which the vehicle passes transmits a message to the vehicle with route data to all of the adjacent beacons one of which is the next routing station. The vehicle receives the message and selects one of the recommended routes which will guide the vehicle towards its final destination. As it executes the travel to the next beacon, it accumulates time and distance traveled which it transmits to the second routing station when it is interrogated by passing the second routing station. In this manner, traffic management is updated in real time and the vehicles are always routed the "best way". Of course the best way may be the shortest way, the less traveled way, the cheapest way or any combination of these plus other criteria.
In Japanese publication JP6208698, from Sumitomo Electric Ind. LTD. dated Jul. 26, 1994, a controller in a motor vehicle operates an automotive telephone device through a modem and a line connection with an information center is performed. When the line is connected, the telephone number of the destination inputted by an operator is transmitted to the information center. The information center transmits a position coordinate corresponding to the received telephone number which is then retransmitted and stored in the controller. The controller reads a map corresponding to the position coordinate from a road map memory by a memory device. A road map is displayed on a display device in the destination facility.